Re: queue_draw_area query..

[Paolo Molaro <lupus ximian com>]

On 04/21/01 Paul Schulz wrote:
> It runs and will update the screen on an expose events,
> (resize, and moving a window in front..)
> but doesn't update the display if I draw on the backing pixmap
> (with update_chart).
[...]
> sub expose_chart {
>   my ($widget, $event ) = @_;
>
>   my ( $event_area );
>
>   $event_area = ${$event}{'area'};

I suggest using:
        my @event_area = @{$event->{'area'}};
and then reference the items as:
        $event_area[0], etc
to reduce line noise.

>   $widget->window->draw_pixmap(
>     $widget->style->fg_gc('normal'),
>     $pixmapChart,
>     ${$event_area}[0],
>     ${$event_area}[1],
>     ${$event_area}[0],
>     ${$event_area}[1],
>     ${$event_area}[2],
>     ${$event_area}[3]
>     );
>
> use Data::Dumper; print Dumper(\ _);
>
> 0;
> }
>
> sub update_chart {
>     my( $widget, $pos, $traffic ) = @_;
>     
>     my $blue_gc = new Gtk::Gdk::GC ( $widget->window );   
>
>     $pixmapChart->draw_line(
>                           $blue_gc,
>                           $margin+$pos,
>                           $height-$margin,
>                           $margin+$pos,
>                           $height-$margin-$traffic
>                           );
>     print "$pos - $traffic\n";
>
>     $widget->queue_draw_area ($margin+$pos, 
>                             $height-$margin,
>                             $margin+$pos,
>                             $height-$margin-$traffic);    

You are requesting the update of the wrong area: in Gtk/X coordinates
start from 0 at the top-left corner. Also, the prototype is

        $widget->queue_draw_area($x, $y, $width, $height);

Changing the code to read:

        $widget->queue_draw_area ($margin+$pos, 0, 1, $height);

makes it work.

> $dareaChart->show;
> $dareaChart->realize;

No need to realize here.
 
> $b = new Gtk::Button("Quit");
> $b->signal_connect('clicked', sub {Gtk->exit(0)});
> $vb->add($b);
>
> $w->show_all;

If you use show_all() on the toplevel widget it's not necessary to 
show the child widgets one at a time earlier...

lupus

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